Four manganese(II) 3-amino-1,2,4-triazole complexes incorporated with different polycarboxylate coligands: Synthesis, structures and magnetism

Four 3-amino-1,2,4-triazole (atz)-based magnetic complexes, {[Mn2(atz)2(nip)2]·2H2O}n (1), {[Mn2(atz)2(Hbtc)2]·2H2O}n (2), [Mn3(atz)2(H2O)12(btc)2] (3), and {[Mn2(atz)(H2O)4(btec)]·2H2O}n (4), (nip2− = 5-nitroisophathalate, btc3− = 1,3,5-benzenetricarboxylate, and btec4− = 1,2,4,5-benzenetetracarboxylate), have been respectively prepared by increasing the numbers of the carboxylate group appended on the phenyl backbone, which were structurally and magnetically characterized by single-crystal and powder X-ray diffraction, elemental analysis, FT-IR spectra, thermogravimetric and magnetic measurements. Structural determinations reveal that complexes 1 and 2 with different polycarboxylate coligands are isostructural, exhibiting 4-connected CdSO4-type frameworks with dimeric MnII2 subunit extended by ditopic μ-N1,N4-atz and carboxylate-containing connectors. In contrast, complex 3 that assembled from the same components as 2 is a discrete trinuclear entity aggregated by two μ-N2,N4-atz ligands. Complex 4 has a layered motif with bent MnII-btec4− ribbons interconnected by μ-N2,N4-atz ligands. Weak antiferromagnetic interactions with comparable coupling constants transmitted by μ-syn, anti-COO− and/or μ-N2,N4-atz mediators were respectively observed in the nearest neighbours of the local bi- and trinuclear magnetic subunits of 1–4.

Four 3-amino-1,2,4-triazole (atz)-based magnetic complexes, two 4-connected CdSO4-type frameworks, a discrete trinuclear entity, and a layered motif, were obtained, exhibiting weak antiferromagnetic interactions transmitted by μ-syn, anti-COO− and/or μ-N2,N4-atz mediators in the nearest neighbours of the local bi- and trinuclear magnetic subunits.Figure optionsDownload as PowerPoint slide